Washington — There are times when Donald Trump manages to be so wrong — so empirically groundless, so logically fallacious, so stridently uninformed — that it seems like a form of parody. But more often than not, this reflects an authentic and alarming ignorance. The mask of a barroom political crank turns out to be the face of the president of the United States.

Such appears to be the case in Trump’s recent threat to cut off hundreds of millions of dollars in foreign assistance to El Salvador, Guatemala and Honduras — countries known as the Northern Triangle of Central America — as punishment for their failure to stem migrant flows to the United States.

To make this action a rational one, Trump must imagine that foreign aid is cash loaded onto cargo planes and dropped on the presidential compounds of corrupt rulers as reward for subservience to American interests. So he wants to cancel the deliveries until they do what we wish.

The reality of foreign assistance is very different. It is seldom given directly to foreign governments. The work is often contracted to nongovernmental organizations that work in partnership with locals. And it is generally designed to improve conditions within foreign countries that can give rise to global threats.

This role is obvious, say, in fighting infectious diseases. It is better to deal with an Ebola outbreak as close as possible to the source, rather than waiting for the threat to arrive in Georgia or Kansas. But this is equally true when it comes to refugee flows.

Consider an example in Guatemala. More than a decade ago, a remarkable institution called International Justice Mission (IJM) — an NGO dedicated to the fight against modern forms of slavery — began working with local authorities to improve the prosecution of child sexual assault. This partnership improved the capacities of police, prosecutors and courts, while making the whole system less traumatizing for survivors. As a result of the initiative — supported by a grant from the U.S. State Department — successful prosecutions in Guatemala have increased by 300 percent, imposing real consequences on predators.

Imagine you had a child and lived in a country where children were raped with impunity. Wouldn’t a dangerous trek northward to America make more sense? But this program and others like it are threatened by the president’s aid cutoff. In the real world of American interests, we need more of these efforts to reduce the supply side of illegal migration. And the supply side of sexual trafficking. And of criminal gangs. And of the drug trade. And of illegal arms dealing. And of radicalism and terrorism.

One of the main drivers of illegal migration has been the collapse of criminal justice systems in Central America. And it reflects a global problem. Gary Haugen, the founder of IJM, speaks of a three-tiered global system. Roughly a third of people in the world live in relatively just and stable criminal justice systems. Another third live under the protection of private security forces — a system that turns security into a luxury good. (In Guatemala, for example, there are seven times more people involved in providing private security than public security.) And a third of people live without the effective protection of the law, experiencing what Haugen calls “everyday violence” from corrupt and exploitative officials.

If American policy does not address the functional collapse of criminal justice systems in places such as the Northern Triangle, it is not seriously addressing the problem of illegal migration. Yet the IJM program in Guatemala and similar efforts are the kind of spending now being threatened by the president’s announcement. This means that American policy has become self-destructive to American interests.

Aid focused on strengthening police forces got a bad name during the Cold War, when such training was sometimes employed by authoritarian regimes for their own purposes. America’s lead aid agency, USAID, was generally forbidden from promoting this type of training. But now the lack of justice leading to everyday violence has become a global problem, with consequences that spill up on many shores, including our own. It is a matter deserving policy creativity rather than Trump’s public threats.

It would make far more sense to double assistance for these programs — designed to support local reformers, not to impose American solutions — than to end them. But an absence of vision is one cost of ignorance.

— Michael Gerson is a columnist for Washington Post Writers Group.